Figure 8: (a) A histological view of the yellow box in Figure 7(a). The depths of three crypts are indicated (yellow arrows and yellow figures). Black arrows and black figures indicate the lengths of the intervening parts. A scale bar is shown at the bottom. Crypt: On a line between the tops of two intervening parts (black dotted line), the point on the line over the center of a crypt was defined as the top of the crypt. The distance from this point to the bottom of the crypt was defined as the crypt depth. (b) A histological view of the yellow box in Figure 7(b). The depths of three crypts are indicated (yellow arrows and yellow figures). Black arrows and black figures indicate the lengths of the intervening parts. A scale bar is shown at the bottom.